Aside from training the quadriceps muscle mass, stretching of the Hamstring muscle and articular retinaculum must be included in the rehabilitation application a single month immediately after trauma. The American Academy of Orthopaedic Surgeons (AAOS) describes the patella can crack in alternative ways, starting from hairline cracks to complete shattering. https://www.theorthopaedicandpainpractice.com/what-are-patella-fractures/